The present invention relates generally to measurement techniques, and more particularly to an improved technique and apparatus for simultaneously and independently performing gas adsorption and desorption measurements on a plurality of different powder samples.
A great variety of applications in modern technology require accurate information concerning the microstructure of materials such as powders which are widely used, for example, as catalysts or in the production of paint, cement, and the like. This information includes the porosity and surface area of the powder material and the distribution of pore volume in the various sized pores.
One conventional manner of performing such measurements, which is disclosed, for example, in U.S. Pat. Nos. 3,211,006 and 3,555,912 involves the preparation of adsorption and desorption isotherms of the material in which equilibrium pressure is plotted against the volume of the gas (typically nitrogen) adsorbed or desorbed on the surface of the material. To prepare such isotherms the quantity of the gas adsorbed onto the solid surface or desorbed from the solid surface is measured at various specified pressures. The conventional gas adsorption process is, however, relatively slow, often requiring hours or sometimes even days to acquire the necessary data to accurately characterize the porosity and surface area of the material.
Such measurements are conventionally performed either manually or by the use of automated equipment on a single powder sample at a time. This results in either slow processing of the materials to make the necessary time-consuming measurements, the expenditure of a considerable amount of time and labor to operate several manual units, or the expenditure of large capital investments to purchase several automated units, so as to permit more than one more sample to be measured at a single time. The need has thus long existed for a unit that is capable of accurately and automatically analyzing the characteristics of a plurality of powder samples both rapidly and at a relatively low cost.
It is thus an object of the present invention to provide an analyzer unit capable of concurrently and independently obtaining data for a plurality of powder samples in a single measuring instrument.
It is a futher object of the invention to provide an analyzer unit of the type described which provides concurrent multiple measurements on powder samples both reliably and accurately and at a relatively low cost.
It is another object of the present invention to provide an analyzer unit of the type described in which the data derived for a plurality of samples can be stored and presented in any one of a number of different forms for each of the samples.